PHYSICAL-PROPERTIES OF LITHIUM INTERCALATION COMPOUNDS OF THE LAYERED TRANSITION CHALCOGENOPHOSPHATES

The layered transition chalcogenophosphates MPX3have recently been shown to function as cathodes in lithium batteries. In this study, we have prepared several members of the series MPX3(M = Fe, Ni, Mn; X = S, Se) in order to observe their physical properties and the effects on these physical properties of chemical intercalation with w-butyllithium. Optical studies have shown that compounds that have a low energy gap behave as good cathode materials: this is the case of FePSe3, NiPS3, and FePS3. For materials with a high energy gap (>2.5 eV) no intercalation is observed. Magnetic studies show no change in the antiferromagnetic characteristics of FePS3, FePSe3, and MnPSe3after intercalation. However, a decrease of magnetic susceptibility observed in LixNiPSs can be explained through the occurrence of multiple phase domains. Optical and conductivity measurements show that intercalations result in the occurrence of negative free carriers that seem to correspond to metallike behavior in the case of Lij.NiPS3. © 1979, American Chemical Society. All rights reserved.